Both Internet Explorer and Firefox at one point were rulers of the free Web. Now, according to data from W3Schools, they're being trampled by Google's Chrome. But the two browsers in second and third place do have one thing in common; they're both fighting to get users back.

The most recent battle started with the launch of Windows 10. When Microsoft users updated their computers, their default browser was switched to Microsoft Edge, and it's not easy to change it back. That's about the same time the maker of Firefox started getting real scrappy.

The CEO of Mozilla, Chris Beard, wrote an open letter to Microsoft's CEO Satya Nadella on July 30, saying, "The update experience appears to have been designed to throw away the choice your customers have made about the Internet experience they want, and replace it with the Internet experience Microsoft wants them to have."

Windows Central rebutted, "Mozilla has started a war of words with Microsoft over Windows 10."

Now, it's possible Microsoft's default browser switch during the Windows 10 upgrade process was just to get people to try out its re-branded Edge browser. It's also possible the move was to give the company an advantage in the browser wars.

Regardless, it set a fire under Mozilla to get an update out stat. Computerworld said the rushed update, "was a turnabout from 2014 when it abandoned years' worth of work on a browser for the touch-centric Windows 8."

Aside from the update, Firefox also put out a detailed how-to on its support site showing Windows 10 users all the steps needed to boot Edge from the default browser position on their machines.

Mozilla and Microsoft's back and forth had little effect on Google. But Mozilla's newest announcement might even get Chrome users' attention, especially considering the growing concern over how peoples' private data is used by the companies they're supposed to trust.

Mozilla announced Friday it's testing out a truly private browsing experience that will "actively block website elements that could be used to record user behavior across sites. This includes elements like content, analytics, social and other services that might be collecting data without your knowledge."

Chrome and Microsoft's versions of private browsing, Incognito and InPrivate, also claim to not keep any information about the sites visited while in use, but not to the same extent. (Video via Mozilla)

Now it's Microsoft's move — or maybe Google, the master of monetizing web data, will get in on the fight. After all, Google stands to lose the most if computer users decide they'd rather not share their data.